Radiotube



June 11, 1929. Y E, A KUEN 1,716,645

RADIOTUBE Filed OGb. l5, 1925 Patented June 11,

UNITED STA In radio tubes as TES PATENT OFFICE.

EUGENE A. KUEN, 0F CINCINNATI, OHIO.

RADIOTUBE.

Application led October 15, 1925. Serial No. 62,550.

in incandescent lamp bulbs, there is always a certain amount of filament stretch or in time during the use of the 5 which employ filaments of this tendeneney is frequently results d sag which takes place tube. In tubes unusual length more pronounced and isastrously by causing a short circuiting of the filament with the grid or other element of the tube,

thereby incapacitating the tube through burning out the filament or otherwise.

Also, in radio tubes therel is a certain amount of filament electron emission which is lost because of electron alignment With the grid for its reception.

to so shape the parts projection out of or plate provided present invention has for an object of the usual electron emissive tube that filament sag may take place Without damaging the ing its operation.

A further object tube orl affectis to produce a radio tube in which considerably greater efficiency of operation is Vobtained with the same elecr tronic action as in other tubes.

These and other objects are attained in the tube described in the following specification and illustrated in `the accompanying drawing, in which:

Fig. 1 is a sectional elevation of a tube embodying my invention.

Fig. also embodying my i ent form.

Fig. 3 is a sectional embodying my invention, but of fied construction.

Fig. 4 is a sectional 2 is a sectional elevation of a tube but of diernvention,

elevation of a tube a modielevation of a tube embodying my invention in a still further modified form.

Fig. 5 is an elevati what reduced scale, of

embodying my invention,

onal view upon a somea double ended tube mounted in a clip or socket Which also constitutes a feature of my invention.

Fig. 6 is a plan vien of the tube and its mounting as shown in Fig.

Fig. 5.

7 is a perspective vien7 .of one of mounting of the I will first describe have shown in Fig. 1,

employed a double tube as disclosed in Fig. 5.

the form of tube I In this tube I have ended construction in which certain terminals, although applying to but one element o out at opposite ends f the tube, are brought of the tube, While the hereinafter more other tube elements have terminal connections at but one or the other end of thetube. The embodiment of the tube consists of an enclosingenvelope Bof glasswhich is provided vvitli sealed ends in which are inwardly projecting stems 9 and 10. In these stems are fused the supporting posts of the filament,

id and plate elements.

Posts 11 and 12 at opposite ends of the tube are provided for supporting the plates 13 and 14. These plates areof especial shape, being of approximate conicalor cup shaped form for iurposes which Will be ully described. I have shown these plates so positioned that their bases or larger ends lie adjacent to the stems at their respective ends of the tube, although the functioning of the tube will be just as effective should they be placed in reverse positions, in parallel positions, `or with both facing in the same direction as shown in Fig. 5.

Posts 15 and 16 are also fused into the stems 9 and 10 and support grids 17 and 18 which are Within and which lie closely adjacent to the inner Walls of the plates, therey also being of substantially conical shape conforming to that of`r the plates.

There now remains but two terminal posts 19 and 20 to which are connected the opposite ends of the filament. This filament has two'eff'ective or electron emissive portions 21 and 22 and a centrally located relatively rigid thickened portion 23 which is located in the brace 24 having its ends fused in the glass stems at the ends of the bases. The effective portions 21 and 22 of the filament are of the usual tlioriated or other especially prepared Wire which is designed for very active electron activity upon being subjected to a current of sufficient voltage. These filament portions are of novel shape inasmuch as they are Wound into spiral shape in general conformance With the shape of the grids and plate. The size of these spiral filament windings is such that they lie closely adjacent to the inside of the grids as do the grids from the plates.

The posts in the stems 9 and 10 terminate in the Wires 25, 2G and 27 at one end'of the tube and in the Wires 28, 29 and 30 at the opposite end of the tube. These Wires are made available for connection with a circuit in which the tube is to be used, by providing terminals 95, 96 and 97 which are shown in Figs. 5 and 6 as molded into bases 98 of bnkelite. Terminals 95 and 97 are iliade in the form of lugs extending from the ends of the tube, while terminal 96 is made in the form of a plate molded in the side of the base. The terminals 95 and 97 are connected with the grid and plate wires 25 and 27 respectively, while plate 96 is connected with the filament wire 26.- At the opposite end ot' the tube the same relationship ho'lds good also. Of course it is perfectly obvious that the terminals 95 and 97 may be mounted in a metal base pro vided theyr are suitably insulated therefrom, the base itself serving as terminal plate 96. I find it convenient to provide. cach of the terminals 95 and 97 with a pin 99 in order that the tube may be easily mounted and a suitable. connection established at the same time. This mounting is accomplished by means of a clip of unique construction which I will now describe.

Each end of the tube is mounted in a clip of the same construction. This clip consists of' a block of insulating material 100 to which the terminals are attached, a portion 101 of the block being provided for the reception of the bolts -102 by means of which the clip is secured to the panel 103 adapted to support the tube. The terminals consist of a pair of spring fingers 104 vand 105 which are attached to the sides of the block and have binding posts 106 and 107 for purposes of circuit connection. Between these fingers is a depending spring finger 108 which is also mounted on the block and which has a binding post 109 for purposes of circuit connection. Fingers 104 and 105 are somewhat diverging and have notched ends 110 and 111 in the form of hooks adapted to engage the pins 99 on the tube terminals 95 and 97. The spring-like action of these fingers is such that the tube when placed in position, will have to be pressed into position to overcome the tension of these lingers, thus causing it to snap into position and to be held securely. In this position the fingers 108 will bear yieldingly against the terminal plates 96 at the' ends of the tube.

The tube shown in Fig. 2 is designed along the same general lines as the tube just described, but contains but one plate and one grid instead of two of each as in the tube shown in Fig. 1. The envelope 41 of this tube is provided with the usual base 42 and locating pin 43, while the contact pins 44, 45, 46 and 47 correspond to the pins of the usual tube. The stem 48 carries the usual posts 49, 50, 51 and 52 which support the plate 53, filament 55 and grid 54 respectively as in other tubes, the posts being connected with the contact pins by the wires shown in dotted lines and which pass through the base. The novel features of the tube consist of course in the shape of the plate and grid, and particularly in the spiral form of the filament, which shapes have been described in the description of the tube shown in Fig. 1.

In Fig. 3 I have shown a tube built somewhat along the lines of Fig. 1; but disclosing the plate and grid elements 56 and 57 at one end with their larger ends facing the larger ends of the plate and grid elements 58 and 59 of the opposite end of the tube. This condition i's just thereverse to the condition shown in Fig. 1, and is done for a purpose which will be described. The filament 60 which occupies the plate and grid elements of this tube is also of the spiral type, but, instead of being of a single conical formation is of a double conical formation adapted to lie closely adjacent to the inner walls of the grids. Posts 61, 62, 63, 64, and 66 support the respective plates, grids and filament 56 to 60 inclusive, while wires 67 to 72 inclusive afford connection of' the respective posts and elements with the circuit in which'the tube is to be placed.

Fig. 4 is a modified form of the invention herein described, in which it shows a tube of dual functioning, but which is nevertheless of single ended or single base construction. In this tube I employ but a single filament having two electron emissive portions 73 and 74 with an enlarged non-effective portion 75 between them. In this respect the tube is like that shown in Fig. 1, except that the two effective portions are brought parallel to one another to form a U-shaped filament. 'lhe central portion 75 of the filament is supported by a lever 76 which is fused into the stem 77 of the base. Surrounding the effective portions 73 and 74 of the filament are the respective grids 78 and 79, while surrounding these in turn are the respective plates 80 and 81. The

grids are supported by the respective posts 82 and 83 which are fused into stem 77, and plates 80 and 81 are supported by posts 84 and 85, while the ends of the filament are supported by posts 86 and 87. I prefer to provide a base 88 of bakelite which, because of the two additional elements which are present in the tube, is admirably adapted to carry in insulated relation two contact pins 89 and 90 as well as the usual contact pins 91, 92, 93 and 94. Wires which have been shown in dotted lines, carry the connection of the tube elements with the proper contact pins.

I will now set forth the purpose of the unusual shape and arrangement of' the tube elements and the manner in which they func- In the functioning of the filaments of radio tubes the material of which the filament is made will. throw off electrons as is well known and upon which the operation of a radio tube depends. This electron emission takes place upon and because of the thus destroying the functioning of the tube 'either temporarily or permanently, or perhaps resulting in a short circuitmg of the filament with a source of voltage sufficient to burn it out and thus render the tube useless. This is particularly truc of t-ubes having filaments of unusual length.` It may also be brought out that in electronic emission from tube elements the direction of emission takes place not only at right angles from the axis of the filament wire, but at various other angles also. For this reason the functioiiing of the grid and plate of the usual tube permits of the escape or at least the utilization of but a portion of theV electrons actually projected from the filament. This is-because of the cylindrical shape of the grid and plate, which leaves relatively large openings above as well as below these elements, through which the electrons may escape.

In the tubes shown in Figs. 1, 2 and 3 the filaments are spirally shaped so that extreme length is obtained with its advantage of greater electronic emission and concentration within the limitations of the short length of plate and grid encompassing it, but, in this spiral shape it is to be noted that the conical shape of the spiral is of particular merit in that it permits of axial sagging of the convolutions of the spiral instead' of sagging sidewise as in the usual filament when elongation or expansion thereof takes place. This avoids the danger of having the filament come into Contact with the grid.

The advantage attained in the double ended forlns shown in Figs. l and 3 is that should t-he spiral sagging of the filament become too great, thereby tending to too great a concentration of electron activity within a limited region of the entire plate and grid surface, as well as tending to produce a point where the filament and grid might touch, it is merely necessary to remove the tube from its mounting clips and to turn it end for end. This then permits gradual restoration of the sagged filament convolutions to normal conditions and allows them to continue to become sagged toward the opposite end of the tube until it is time to reverse the position of the tube again. This sagging is however of a very limited nature and in fact would never occur except in the event that the filament is subjected to an excessive voltage. The actual tendency however is for thefilament convolutions` to restore themselves to normal shape and condition each time the filament is allowed to cool, because of the spring-like action of the spiral winding.

In Fig. 3 I have shown the large open ends of the lplates and grids as facing each other and spaced apart but slightly. This condition is for the specific purpose of rendering the operation of the tube more efficient than has been heretofore. As I have set forth heretofore, the projection of electrons from` a heated filament occurs at all angles therefrom. For this reasonthe substantial enclosure of the filament by the conically shaped plate and grid elements opcrates to catch and utilize substantially the entire delivery of electronsl from the filament whether such delivery be upward, downward, sidewise orat angles intermediate thereto. Of course this form of the tube is designed to give two tube functioning because of the presence of two grids and two plates, but the same results as far as the relatively complete utilization of projected electrons may be obtained should it be desired to use the tube as a structure having but one filament, one grid and one plate, by merely connecting the two plates together to operate as one and by connecting the two grids together to operate similarl might be of advantage, should it be desired tohave such a tube to function as a single tube with filament enclosing grid and plate elements to purposely construct the grid and plate'elements in the form of double cone, spherical or other filament enclosing shapes, particularly if the filament is of a shape substantially such as I have set forth.

And now, in Fig. 4 the use of a long filament is shown, but of novel form for use in a single ended tube, but employing multiple grid and plate elements so that the tube may function as more tube. For example` the embodiment shown is that of a tube having two grids and two plates with but one filament having two effective portions, one for each set of grids and plates. Thus, although one long filament is employed, by enclosing each relatively short etl'cctive portion of the filament in a closely surrounding grid and a. correspondingly close plate substantially as effective efficiency of electron utilization is obtained as with the types shown in Figs. 1 to 3 inclusive.' However, in view 'of the limitation in size of the filament portions and. the grid and plate cooperating with each, the individual units of the tube will handle but a portion of the work done by the tubes previously described. Such a may be made to handle a much greater ,volume by connecting the two plates to operate as one and the tw'o grids to operate as one in the same manner. In using the tube so that each unit thereof functions independently, the separate units may be,l em- However it than one ordinary A tube permit of a quick,

ployed to operate as radio frequency amplifiers or as detectors, while When used jointly as one the tube adapts itself admirably for audio frequency amplification. It might be mentioned that the tubes shown in Figs. l to 3 inclusive will function in all three capacities, although for audio frequency amplification the latter is notably successful. The double ended or two unit types shown in Figs. 1 and 3 are remarkably valuable for use in push pull audio amplification circuits, in which the heavy loads impressed upon the two units of the tube will be easily carried because of the large size of the elements, in addition to the :fact that the set of elements in each unit is functioning under exactly the same conditions of load, vacuum, filament, voltage and other factors, as the cooperating set of elements, the balancing of these two units being thereby rendered perfect.

In order that my improved form of double ended tubes shown in Figs. l and 3 may` be properly mounted, I have shown in Figs. 5 to 7 inclusive an improved -clip which will easy, cheap and electrically eflicient placing and holding of the tube in position in a set embodying a circuit in which the tube is to be used. This has been described above.

The arrangement of the filaments shown in my improved forms of tube may be likened much to a stream of Water through a hose. If the volume of water is great and has to pass through a restricted hose in a giventime, it will be projected from the hose in a forceful stream, thus throwing it to a great distance. However, a small volume of water passed through the same hose in the same time may merely drip from the hose in leaving it. So it is with electrons projected from the. spiral filaments I have shown. The quantity of electrons projected from such a source will be great and In Fig. 5, as I have mentioned above, both clement units are shown as facing in theA same direction. There is an advantage to be obtained by this, because when the filament coils sag they will tend to Sag toward the larger end of the tube units and thus prevent any chance of the tube becoming short circuited as well as overcoming the necessity of having to reverse the position of the tube from time to time because of this, as has been explained.

In Fig. 3, as has been explained above, I show the two conical units connected by elements represented by dotted lines. This makes the entire tube function as having but one set of elements. Therefore, it may now be considered that a tube such as I have shown in Fig. l, could just as readily have two complete dual units of this description as to have the two sets of single units of open ended type which have been shown.

Thus it is that mylinvention may be capable of many deviations from the exact illustration and description I have given it, without departing from the spirit and scope of the claim which now follows.

I claim:

A radio tube comprising a filament having more than one electron emissive portion, each portion consisting of a vcup shaped formation, adjacent portions being separated by non-emissive support portions, and grid and plate elements corresponding in general shape to that of the emissive portions for cooperation therewith.

In testimony whereof I have hereunto atiixed my signature.

EUGENE A. KUEN. 

